Inherit EventTarget interface instead of duplicating its code

Source/modules/webaudio/AudioNode.h

Index: Source/modules/webaudio/AudioNode.h
diff --git a/Source/modules/webaudio/AudioNode.h b/Source/modules/webaudio/AudioNode.h
index 9be358d9b3d5029dce401c736b180d9f1f4853f5..2d3c2b39c82dbd61c1d67f59e99375f40867acf3 100644
--- a/Source/modules/webaudio/AudioNode.h
+++ b/Source/modules/webaudio/AudioNode.h
@@ -51,7 +51,7 @@ typedef int ExceptionCode;
 // An AudioDestinationNode has one input and no outputs and represents the final destination to the audio hardware.
 // Most processing nodes such as filters will have one input and one output, although multiple inputs and outputs are possible.
 
-class AudioNode : public ScriptWrappable, public EventTarget {
+class AudioNode : public EventTarget, public ScriptWrappable {
 public:
     enum { ProcessingSizeInFrames = 128 };